Draftsman&#39;s protractor



' D. 6.. LOPEZ DRA FTS.MANS PBOTRACTORI APPLICATION'FILED SEPT- 13, 1919.- RENEW-ED JULY 22, I920.

Patented Aug. 31, 1920.

2 SHEETS-SHEET 1.

D. C. LOPEZJ DRAFTSMAN'S PROTRACIOR APPLICATION FIILED SEPT. 13. 1-919. RENEWED JULY 22, 1920.

Patented Aug. 31,1920.

2 SHEETS-SHEET 2.

UNITED stares] DA ID oABnERA'LorEz, or CHICAGO; rLLmoIs.

. nmrrsnans 'rno rnaeron} Specification of Letters Patent. Patgntgd A g, 31," 1 20 Application filed September 13, 1915, Serial No. 323,468.. Renewed July 22, 1920. Serial No. 398,285;

useful Improvements in Draftsmens Protractors; and. I do hereby declare the following to be a full clear, and exact descriptlon of the invention, such as will enable others allel.

skilled in the art to which it appertains to make and use the same.

This invention relates to an improvedprotractor for use by draftsmen and the princi- I bolt.

pal object of the invention is to provide a protractor so constructed that it may be used in connection with a T-square or ruler and ther so construct this protractor that by use of the same a line may be drawn at an angle which will produce a desired taper or drop per foot.

In machine work it is often necessary to provide a given taper per foot and in architectural work it is often desired to have a floor constructed at an incline or in other. words have a drop of a certain amount per foot and withthis improved protractor the necessary angle to produce the drop or taper per foot can be easily ascertained.

Another object of the invention is to provide an improved joint construction for pivv otally connecting the arms or legs of the protractor, the joint being so constructed that the arms may be easily swung to the de-" sired position and then securely locked in the desired position thus preventing the arms from moving while in use. J

Another object of the invention 1s to so construct this joint that the arms of the protractor may be disconnected when necessary for cleaning and 011mg the joint.

Another ob ect of-the invention is to so construct the joint th'atthe head of the screw or threaded stem forming the pivot pin will be locked against rotary movement independent of one of the arms and thereby pre vented from turning when the securing nut is tightened or loosened. V I This improved protractor is illustrated in the accompanying drawings, wherein:

Figure 1 is a top plan view showing the protractor with the. arms extending par- Fig. 2 is a view similar to Fig.1 with the arms extending at right angles to each other.

.of the protractor. F g. 5 is a plan view upon the paper.

Fig. '3 is sectional view through the joint taken along the line 3-3 of Fig. 1.

Flg. 4: 1s a plan view of one of the sections of the second section. F 1g. 6 1s a sectional view through the head of one of the sections taken alongthe line 66 of Fig. 4i. i

Fig-7 is a view similarto Fig.6 taken alongthe line 77 ofFigQ5.

Fig. 8 is a view of the spring disk which 1 locks't'he securing nut in place. 1

Fig. '9 is a side elevation of the pivot This improved protractor is provided v with two sections indicated in general by the a l1ne drawn at a desired angle and to furnumerals 10'a nd 11 and provided with arms 12 and 13 which extend from head or joint elements 14 and 15. These heads will'be ro-i tatably connected, as hereinafter brought out, thus pivotally mounting the sections and permitting them: to be turned to place the arms either parallel, as shown in Fig.1,

or at an angle, the limit of the angle being ninety degrees as shown in Fig. 2.

The section lQ has' its head 14 provided This section 13 has its head 15 provided with a central opening 18 through which the neck portion thereof provided with a flat under face extending in-the same plane as the arms thus permitting the protractor to rest flat A disk'21 which serves as] a dial is positioned upon the collar 19 and secured thereto by screws or other removable fasteners 22 which pass into threaded openings 23 formed in the collar thereby holding or bearing 19 of the head 14 passes and'has I the disk in position to retain the heads in engagement as shown in Fig. 3, but permitting the disk to be removed when itis desired to separate the sectionsfor cleaning. The dial is provided with scale rnarki 'igs, as shown in Figs. 1 and 2, which will cooperatefwith' similar scale markings upon the outer face of the head 15 to indicate taper per foot when the arm 12 is swung from the position shown in Fig. 1 toward that shown in -Fig. 2 as will be hereinafter brought out.

scale in degrees is also provided upon the outer face of'this head .15 atathe edge there- V of, as shown in Figs. 1 and 2, and cooperates with a scale marked upon the flange 2 10f the head 14 to indicate the angle at which the arm 12 extends in respect to the arm'18,

' as will be hereinafterbrought out.

In orderto secure'thesection of the. pro

ftractor in a set position with the arm 12.-

extending at the desired angle tothe arm 13, therehas been provided; a screw which has a-head 25, the edge ofwhich'is beveled. and fits into the 'under cut opening 16 of the head 14L. A neck 26 extends from this head 25 through theopening 27 of the dial 21 and has its upper face flush with the upper face ofthe dial as shown in Fig. 3. The threaded stem 28-of the securingscrew extends upwardly and carries a securing nut 29, a spring Washer 30 being placed upon the threaded stem between the nut-and dial and serving to lock the nut against accidental turning to release'the fastener when the protractor is in use. Normally; this spring washer is curved transversely from the outer edge toward the central opening 3.1 through which the threaded stem 28 v oasses but when the securin nut is ti htened the washeravill be flattened as shown in Fig. 3 thereby providing the necessary binding action to lock the nut. In. order to prevent the screw from turning in the openings 16 and 27 when the nut is turned to tighten or release the fastener, there has been provided a lug 32 which fits into the offset or pocket 33 of the opening 16. Therefore, the securing nut can easily be tightened or loosened and there will be no,

danger of the screw turning with the nut thus. preventlng'proper tlghtening of the nut or making 1t very 'd1flicult to release 7 the nut after it has been tightened.

:produce the desired taper or drop per foot or at a desired angle up to ninety degrees When in use, the protractor will be first set as desiredand will then be placed upon the paper with one of the farms in engage -ment with the side edge of a T-square blade. A line can therefore be drawn with the second arm used as a ruler: and the line wlll be drawn at the necessary angle to with respect toa line already drawn. If it is desired to have the line drawn parallel to a given line, the protractor will beset as shown in Fig.1 with the arms extending parallel, but. if it is desired to have this linev extend at an angle to the given, line,

thearm 12 will bev swung away from the arm. 13 towardthe position shown in Fig.

2 until the cipher of the scale upon flange QLregisters with the degree upon the scale at the edge of the head 15 at which it is desired to have the line extend. For in stance, if it is desired to have the line at right angles or at ninety degrees to the given line, the arm will be'swung to-the position shown in Fig. with the cipher registering with the ninety degree mark.

The'nut will then be tightened and the two *sections will be securely held in the desired 1 position. In the same way ifitj is desired to have oneline extend parallel to a line extending at an unknownangle the protractorcan be placeduponthe paper with the edge of one arm engaging the edge of :the T-square which. will be positioned to extend acrossthe board. The second arm will .then be. swung until the; edge thereof allel tothe same can be drawn.

produce a desired'taper perfoot 01% drop in a floorlng per foot, the fastener w1ll be released .and the arm 12 swung until the corresponding mark upon the dial 21 and inner edge portionofthe head 15 register. For instance, if it is desired to produce a line which Will give a drop 'of three-eighths of an inch taper per foot, the arm 12 will be swung until the three eighths inch mark of the dial registers with the three 7 eighths inch mark of the head 15. then be tightened and-the line will be drawn at the right angle. It will thus be seen that there has been provided a protractor so constructed that it can be used either for drawing a line at a given angle to a line already drawn or a 'li'ne'may bejdrawn at .an anglewhich will give a desired taper or drop in inches or fractions thereof per foot. There has further been provided a protractor which is so constructed that it will rest fiat upon the paper andmay be very efliciently used in connection with a T-square. It will be further noted that the protractor is so constructed that'it can be turned and securely set in the desired position and at the same time' the joint may be taken apart thus permitting the sections of the protr'actor to be disconnected for clean ing and repairing.

What 1s claimed 1s: 1. A protraetor comprising sections each The fastener will having an arm, a headcarried 'byiea'ch arm,

the head of one arm' being provided with "a central openlng undercut and the head being further provided with a circular seat in its npper face positioned about the central open mg and in spaced relation thereto to provide a collar about the opening, the headof the "second arm fitting into the's eat of the first head and provided with a' central opening "receiving the collar of the first head, a disk,

secured upon the collar of the first head and providing a dial overlapping the outer face of the second head to rotatably hold the second head in engagement with the first hpad,

said dial being provided with a central opening registering with the central opening of the first head, and said dial being provided jacent its outer periphery with scale markings coiiperating with the scale markings upon the outer face of the first head, a fastener having a screw provided with a head fitting into the undercut openingof the first head, a collar carried by the head of the screw and fittin into the opening of the dial, a, threaded stem extending from the collar,'a locking washer upon the threaded stem engaging the disk, and a securing nut screwed upon the threaded stem and engagmg the locking washer.

2. A protractor comprising sections each having an arm and a head, the head of one arm being providedwith an annular groove in its outer face providing a seat and the head of the secondsection fitting into the seat of the first head and having a central cut out through which the central portion of the first head passes, a disk connected with the central portion of the first head and extending in overlapping relation to the head of the second section to rotatably connect the head and pivotally mount the sections, a,

fastener carried by the central portion of the first head and having a threaded stem, a securing nut screwed upon the threaded stem, and a locking washer upon the stem between the securing nut and disk, the fastener when tightened holding the sections against pivotal movement. I

3. A protractor having sections each provided with an arm and a head, the head of one section being seated in an annular groove formed in the head of the second section and having its outer face provided adjacent its outer peripheral edge with scale markings in degrees cooperating with the scale markings upon the head of the second section for indicating the angular relation at which one arm extends with respect to the second, a disk connected with the centralportion of the second head and overlapping the head of the first section and having scale markings thereon cooperating with scale markings upon the inner peripheral edge portion of the first head to indicate the taper of an object drawn through the medium of the protractor, and means for securing the sections against pivotal movement.

4. A protractor comprising sections each having an arm and ahead, the head of one arm havinga central opening having an olfcured to the central portion of the head of the first arm and overlapping the central portion of the head of the second arm head, a fastener,- screw having an enlarged head positioned in the opening of the first head and having a finger extending into the pocket to hold the screw against rotation, a collar extending from the head of the screw through the opening in the disk and provided with a threaded stem extending beyond the outer face of the disk, a locking washer upon the stem engaging theouter face of the disk, and a securing nut screwed upon the stem and engaging the washer, the fastener when tightened drawing thedisk into tight engagement with the head of the second section to' hold the sections against pivotal movement.

5. A protractor comprising sections each having an arm and a head, the heads being positioned 1n overlapping relation, adisk set forming a pocket,the head of thesecond V arm being positioned in overlapping relation to the head of the first arm, a disk secarried by one head'and engaging the secs I end to rotatably connect the heads and pivotally mount the sections, the head of one section being provided with scale markings cooperating with scale markings upon the dial and the head of the second section to indicate the angle or pitch of a linedrawn through the medium of the protractor, and

fastening means formoving the disk into blndlng engagement with the head of one section to retain the sections against pivota movement after being adjusted.

In testimony whereof I affix my signature in presence of two witnesses.

7 DAVID OABRERA; LOPEZ. Witnesses: f v

ALBERT F. MILLER, ETHAN L. CLARK. 

